1. Field of the Invention
The present invention relates to a rotating shaft structure for a screen and a foldable portable electronic device, and more particularly, to a rotating shaft structure for a screen and a foldable portable electronic device, which can increase the torsion for a specific angle range during the cover opening/closing processes.
2. Description of the Related Art
Foldable electronic devices such as notebook computers are electronic equipment commonly seen every day. When a user tries to open or close a cover of a notebook computer, due to its foldable design, the user has to apply suitable torsion to successfully open/close the cover.
Please refer to FIG. 1 for a view illustrating a relation between the pivoting angle and the torsion value of a prior art rotating shaft structure. In FIG. 1, the horizontal axis denotes the pivoting angle of a foldable electronic device, the vertical axis denotes the torsion value, the upper curve denotes the cover opening process, and the lower portion denotes the cover closing process. The characteristics of a traditional rotating shaft structure for a screen are the symmetrical relationships between the torsion curve representing the cover opening process and that representing the cover closing process. That the torsion value of segment AB equals that of segment GH, and the torsion value of segment CD equals that of segment EF.
However, in some cases, it is necessary to increase the torsion for a specific angle range. For example, when a user uses a notebook computer with a touch screen, it takes more torsion for the user to turn the cover open to an operation state (with the pivoting angle ranging from, for example, 100 to 130 degrees). However, it takes less torsion to close the cover during operation. On the other hand, when the cover closing process proceeds to a specific angle range (with the pivoting angle ranging from, for example, 70 to 30 degrees), it requires more torsion to support the screen to prevent accidental falling of the screen due to the user releasing his/her hand and the resultant damage to the internal structure of the notebook computer.
However, presently there are no designs available to form asymmetric torsion curves related to the cover opening/closing processes respectively. That is, it is not possible at this time to increase the torsion of the rotating shaft structure for specific angle ranges during the cover opening/closing processes to facilitate the user's operation.
Therefore, it is necessary to provide a rotating shaft structure for a screen and a foldable portable electronic device to solve the problems of the prior art techniques.